High-manganese steel with low carbon.



' nese steel in order to avoid cracks therein or I or when they arebeing heated preparatory to in carbon, that is, containing say less thanROBERT ABBOTT HADFIELD, OF SHEFFIELD, ENGLAND.

HIGH-MANGANESE STEEL WITH LOW CARBON.

Specification of Letters Patent.

Patented June 11,1907.

Application filed April 16, 1907. Serial No. 368,583.

To all whom it may concern.-

Be it known that I, ROBERT ABBOTT-HAD- FIELD, a subject of the King ofGreat Brit-v ain, and a resident of Sheffield, county of York, England,have invented an Improve-'- ment in High-Manganese Steel with LowCarbon, of which the following description, in connection with theaccompanying drawing, is a specification, like letters on the draw-- inrepresenting like parts.

In the manufacture of .high manganese steel, wherein the product isrequired to contain, say, from 10% to 14% and upward of. manganese ithas not heretofore been found practicable, orindeed commerciallyossible, to kee the percentage of carbon as ow as is desira le.

As a consequence of the comparatively and undesirably high percentage ofcarbon (owing to the common use of ordinary ferro-manganese, containingfrom 6% to 9% of carbon) and'because of the fact that manganese steel isa bad conductor of heat,- it results that great care has to be taken intreating castings and forgings made from such high manga-.

fracture thereof when they are being cooled,-

being subjected to a water toughening process, as well as during suchprocessand thereafter. In the course of my studies and exeriments toovercome such objectionable features due to the high percentage ofcarbon in such steel I have discovered that by using, in the manufactureof steel of the character specified, an alloy of manganese and iron low2% to 3% of carbon, instead of the ordinary ferro-manganese, I amenabled to produce a magnetic .high manganese steel in forms result isdue to the fact that owing to the comparatively low percentage of carbonin the manganese steel made in accordance with my invention the steel isrendered much less liable to fracture during the cooling, or heating andcooling treatment for toughening it hereinbefore mentioned, and suchsteel is distinguished by its relatively strong magnetic character.

' A low carbon manganese-iron alloy suitable for use in the manufactureof high manganese steel in accordance with my present invention is thatnow produced in the electric furnace and which contains usually from to(seventy to ninety percent) of manganese with less than 2% to 3% (two tothree percent) of carbon. 1 1: 5

In carrying out my invention low carbon manganese-iron alloy such asspecified is added, referably in a molten condition, to a base 0 moltendecarbonized iron, such as that used in the production of acid steel,and from which practically the whole of the carbon, silicon, andmanganese have been eliminated in suitable manner, as for instance bythe pneumatic or the open hearth method. The manganese alloy and theiron are preferably weighed in' molten condition to insure that theresulting manganese steel shall accurately contain the desiredpercentage of manganese. The manganese steel thus produced is thenpoured into molds to form castings, or into molds to form ingots whichare forged in any suitable manner requisite for dealing with manganesesteel. I

By the process described I am enabled to produce in a practical mannerand on a commercial scale a manganese steel having a much lower ercentae of carbon than heretofore, and w ch stee can therefore be easily andreadily heated and cooled with much less liability to fracture thanheretofore.

A further advantage resulting from my invention is'that articles can besafely made of much thicker sectionv of the improved manganese steelthan of ordinary manganese 1 steel. Thus, owing to the difficultieshereinbefore mentioned, and to the fact that higher percentage of carbonin manganese steel as heretofore made tends to prevent as perfect orcomplete a toughening as is desirable, it has not heretofore beerfpossible to produce on a practical scale, from high manganese steel,articles of more than about three or four inches in -thickness when thesame reuired toughening. On the other hand artic es canbe made of theimproved steel herein described of much thicker section while admittingof theirbeing properly toughened. The steel made in accordance with myprescut invention is characterized by its rela- 3 If desired themanganese steel inanufaclured in accordance with my invention maycontain other elements than iron, manganese and carbon, as for example,it may contain nickel, chromium, tungsten, molybdenum and vanadium invarying proportions, say from one-tenth of one percent to thirty percent (1% to 30%).

Having fully described my invention, What I claim as new and desire tosecure by Letters Patent is: I

1. The herein-described steel containing] less than 1.0% of carbonand/from 10% to 14% of manganese, capable of being reai'lilyheet-treated and toughened in the mass with- I out cracking,andilistinguished by its relatively strong magnetic character.

2. The herein-described steel containing less than 1.0 of carbon and ahigh percentage of manganese, distinguished by its relatively strongmagnetic character, and cnpable of being readily heat-treated andtfliiglh ened in the mass without cracking.

In testimony whereof, [have signed my name to this specification, in thepresence of two subscribing witnesses. V

ROBERT ABBOTT IIA DFIELI).

Witnesses:

PERCY PHILLIPEPS, 'ALFR n NUT'rmo.

